Lovely vidoe Dave. Seen a simpler circuit, for industrial logic where the designers decided to go even easier. They used a 555 timer, and use pin 3 to operate the relay, 150R coil, and also have a 180R 2W resistor to the other power rail. Set of pads which are drilled out during manufacture, and a second place for the resistor, so that you can decide if the relay is to be normally energised or normally deenergised on power application. Power on some is via a tiny mains transformer, 110VAC primary, or 24VAC primary on some, to a 12VAC secondary, and a simple bridge rectifier and 220uF 25V capacitor for smoothing. There are also 24VDC versions, where they use another 180R resistor as a dropper from 24VDC, with a single diode in the bridge to provide reverse polarity protection. Same PCB for all the dozen or so timer variants, you just cut tracks for relay operation, and use either transformer and bridge, or resistor and diode, as the pin spacing matches on all those options, and where you connect power.
Modules all date from the late 1970's, it was a job lot I got on auction for around $5, for around 500 modules, so they have been supplying all my relay needs for a long time, provided I can use the 12V or 24V relays, and get to look for whatever is needed, generally DPDT with 5A contact ratings, though some are SPDT as well. Just have to bear with the 150R coils on 12V, and 300R coils on 24V. A lot of vintage 555 and 741 IC's in there, all well aged, but pretty much all do work when tested. Even used some in industrial control as well, as they were around, and I had the right 8 pin or 11 pin bases.